Structural, electrical and magnetic properties of the pyrochlorate Er_2-x Sr_x Ru_2O_7 (0<=x<=0.10) system

Abstract

In this research, we report a detailed study of the structural, electrial and magnetic properties of the ruthenium pyrochlore with the composition (Er_2-x Sr_x) Ru_2O_7 0<=x<=0.10 prepared by solid-state reaction in air at ambient pressure.  The synthesized products were characterized using powder X-ray diffraction. The structure of the samples was refined with the Rietveld method, showing that the lattice parameters are more sensitive to the Strontium and Erbium sites. Scanning electron microscopy shows that the crystal size varies between 0.27 and 0.62 mu m. In all polycrystalline samples, the electrical resistance decreases with increasing temperature, indicating that the samples are nonmetallic. The slope of the temperature-dependent resistance profiles systematically decreases with increasing x, proving that the carrier concentration increases with increasing the Sr content. Zero-field-cooled and field cooled magnetization measurements show an irreversible behavior where the split is systematically enhanced by increasing x.